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$10 Drawdio 

Makej Projects 

$10 Drawdio 

Written By: William Anderson 


Helping hands or third hand tool (1) 

Soldering Iron and rosin core solder. (1) 


(clear or electrical) 

Wire cutter and stripper (1) 

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8 Ohm mini speaker (1) 
Stranded Core Wired) 
(24 to 22 gauge) 
2N3904NPN transistor (1) 
2N3906PNP transistor (1) 
0.01 uf disk capacitor (1) 
marked "103" 

30k resistor (orange black orange) (3) 
(or 1 100k resistor, or 4 22k resistors; 

4.7K resistor (yellow purple red) (1) 
Battery holder for 2 AA batteries (or 
AAA) (1) 
Aluminum foil (1) 
Pin (1) 

Electrical Tape (1) 
Regular pencil (1) 
(2B works best) 
(optional) circuit board (1) 
(if you want the circuit to be a bit more Page 1 of 6 

$10 Drawdio 


(Optional) heat shrink tubing (1) 

(to cover the connections so nothing 

shorts out) 

Velcrotape (1) 

Zip tied) 


These instructions will teach anyone that reads these how to make a drawdio with spare 
parts. It will cost $0-10 to make this little noisemaker. All of the parts can be obtained at 
RadioShack or any old electronics. 

Step 1 — Solder up the 3904 

• Hold the 3904 in a helping 
hands and solder the base I 
(middle) pin to one end of the 4.7k 
resistor. Then solder the collector 
(right, as you read the markings) to 
a 2 inch wire and to 1 of the 30k 
resistors. Lastly, solder the emitter 
(left) pin to the negative (black) 
wire from the battery holder and 
one wire from the speaker. 

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Page 2 of 6 

$10 Drawdio 

Step 2 — Solder up the 3906 

• Solder the base (middle) pin of the 
3906 to the 2 inch wire you 
soldered in the last step. Solder the 
emitter (left) pin to the positive 
(red) wire from the battery holder. 
Finally, solder the collector (right) 
pin to the other wire on the speaker 
and one lead of the 0.01 uf 

Step 3 — Solder up the last connections 

• Solder the other lead from the 
capacitor to the other lead on the 
4.7k resistor, and then solder a 3-4 
inch wire in-between the 
connection you just made. 
Remember the 30k resistor you 
soldered earlier? Solder another 
30k resistor to that one (the first on 
you soldered). Repeat again with 
the last 30k resistor by soldering it 
to the other lead of the one you just 
soldered. Solder a 3-4 inch wire to 
the last 30k resistor. (Optional) 
Cover everything in heat shrink 
tubing or electrical tape. 

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Page 3 of 6 

$10 Drawdio 

Step 4 — Mount the circuit to the pencil 

• Put the end of the zip tie through the locking part and use it to mount the circuit to the 
pencil. Use tape if the circuit keeps moving around. Strip one of the wires and wrap it 
around the pin's metal part. Push the pin into the pencil until your're sure that the metal 
part of the pin touches the inner graphite. Then tape down a layer of foil on the part of the 
pencil that is below the circuit. Sandwich the other wire in-between the bottom layer of foil 
with another layer of foil. Make sure you don't cover most of the foil! (Unless it is 
conductive.) Your're done! 

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Page 4 of 6 

$10 Drawdio 

Step 5 — Play it 

• Make a dark line on a piece of paper. Hold the drawdio by the foil. Touch the pencil 
graphite to the line. Touch your other finger to the line also. You should hear a noise. 
Notice that when you move your finger or the graphite closer of farther away, it raises or 
lowers the pitch. If it doesn't play, check your work. Is there a short? Did the little 
connections break? If it's not working, not much can go wrong. 

Step 6 — Remix it. 

• You can put it in a jacket, or a 
paintbrush, or a tree, or even the 
kitchen sink... The ideas go on and 

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Page 5 of 6 

$10 Drawdio 

Step 7 — Resources 

i If you want to buy drawdio kits visit the makershed at (Here I also use 
the drawdio in the makershed in the last photo.) If you want to see how the drawdio got 
first invented and/or the drawdio in action, go to Jay Silver's website at 
Happy Making! 

st generated on 2012-10-31 11:42:03 PM. 

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